1. Field of the Invention
The present invention relates to a magnetic disc apparatus and more particular to a disc apparatus provided with an aerodynamic latch mechanism.
2. Description of the Prior Art
In the magnetic disc apparatus, there is a case that an aerodynamic latch is used for fixing an arm at a time when a disc is not rotated and canceling the fixation of the arm at a time when the disc is rotated. This is structured such that the fixation of the arm is cancelled by utilizing a force of an air stream generated due to a rotation of the disc.
As a prior art, there are Japanese Unexamined Patent Publication No. 4-228158 and U.S. Pat. No. 4,538,193. In Japanese Unexamined Patent Publication, the structure is made such that an air stream generated due to a rotation of a disc is directed to a passage being adjacent to the disc and narrowed gradually, by using a fixed air vane protruding into the disc, and the air stream strikes against an air vane provided on the passage so as to move an angle and release an actuator assembly. That is, the air vane is provided so as to clog a flow passage of the air stream, and the air flow passage is set to a clogged direction even in the case that the angle is moved.
Further, in U.S. Pat. No. 4,538,193, the structure is made such that a wind blade which is exposed to an air stream at a time when a disc is rotated and can rotate with respect to a predetermined shaft is protruded into a disc rotating disc, and an actuator lock is released by utilizing the air stream generated due to the rotation of the disc.
However, in the structure described in Japanese Unexamined Patent Publication No. 4-228158, the air vane clogs the air stream from the disc, and there is provided the fixed air vane protruding to the portion between the discs. Accordingly, since the stream between the discs is disturbed, there is a problem that a consumed electric power is increased and a disc vibration (hereinafter, refer to xe2x80x9cflutterxe2x80x9d) caused by a fluid is generated. Further, in the structure described in U.S. Pat. No. 4,538,193, since the air vane protrudes to the portion between the discs, the same problem exists. In addition, there can be listed up problems such that the air vane occupies a wide space within the apparatus, the number of the parts is increased, a producing cost is increased and the like.
An object of the present invention is to solve the problems mentioned above and to provide a magnetic disc apparatus which is compact and is provided with an aerodynamic latch mechanism having a high performance.
In order to achieve the object mentioned above, in accordance with the present invention, the structure is made such that an aerodynamic latch is provided in an outer portion of a magnetic disc, a front end portion exposed to a wind of the aerodynamic latch is opposed to an outer peripheral end of the magnetic disc, an air flow passage is formed between a portion exposed to the wind of the aerodynamic latch and a housing or a rectifying plate at a time when the aerodynamic latch is operated, and an air stream flows along an outer periphery of a rotary actuator.
Further, the structure is made such that a shroud is provided between the rotary actuator in a side where the aerodynamic latch is provided and the disc.
Further, a ramp mechanism for loading and unloading is arranged so as to constitute a part of a return flow passage of the air stream passing through the aerodynamic latch portion. Further, the air flow passage is integrally formed with the housing and a rotary shaft of the aerodynamic latch portion is mounted to a voice coil motor (VCM), thereby reducing the number of the parts.